This application is related to and claims priority from Japanese Patent Application No. 2000-260231, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a glass run for attachment to a door of a motor vehicle.
2. Description of Related Art
As shown in FIG. 1, a conventional glass run 10 is attached to a door frame 12 around a window opening of a vehicle door 14 and frame members 16a, 18a which extend from the lower ends of a front vertical portion 16 and a rear vertical portion 18 of the door frame 12 into a door panel of the vehicle door 14.
As shown in FIG. 2, the conventional glass run 10 includes a main body 20 having a generally U-shaped cross-section, and seal lips 22 and 24 which extend obliquely inwardly from open ends of side walls 26 and 28 of the main body 20.
A channel 30 having a generally U-shaped cross-section is provided along an inner periphery of the door frame 12. The frame members 16a, 18a in the door panel also have a cross-section substantially identical to that of the channel 30.
The glass run 10 is attached into the channel 30 of the door frame 12 as well as the frame members 16a, 18a extending into the door panel. The glass run 10 serves to guide a door glass 32 as it is raised and lowered, and form a seal between a periphery of the door glass 32 and the door frame 12 when the door glass 32 is raised to close the window opening of the vehicle door 14.
The glass run, particularly the substantially vertical portions, is required to provide low sliding resistance against the door glass as it is raised and lowered therealong. To achieve this low sliding resistance, films of various lubricating agents have been formed on at least the contact surfaces of the seal lips. With this reliance on lubricating films, however, the sliding resistance may still exhibit undesirable increases.
In a conventional arrangement, the increase in the sliding resistance is mainly caused by the door glass pushing the seal lips toward facing side walls of the glass run so that projecting ends of the seal lips are pressed against an inside surface of at least one of side walls.
The door glass and the door frame are generally arranged to curve gently in conformity with a side surface profile of the vehicle body, and to incline the top portion toward the interior of the vehicle body. Accordingly, an inevitable difference in curvature is created between at least portions of the door frame and the door glass. Further, variations in the attachment position of the door glass may also occur, causing the door glass as it is raised or lowered along the glass run to be offset toward at least one of side walls. Consequently, the projecting end of one seal lip will be pressed against a facing side wall.
In particular, where, as shown in FIG. 2(A), the seal lip 22 of the glass run 10 is longer than the seal lip 24, the longer seal lip 22 is pushed by the door glass 32 so that, as shown in FIG. 2(B), a projecting end 22a of the seal lip 22 is strongly pressed on the inside surface of the side wall 26, and consequently, the projecting end 22a of the seal lip 22 will not slide easily along the inside surface of the side wall 26 toward a bottom wall of main body 20. When this occurs, the door glass 32 is unable to push the seal lip 22 further toward the side wall 26, resulting in an increased pressing force between the door glass 32 and the seal lip 22 that increases the sliding resistance of the glass run 10 against the door glass 32.
Furthermore, where, as shown in FIG. 2(A), the side walls 26 and 28 are tapered to gradually decrease the distance therebetween toward the bottom wall of the main body 20, the projecting end 22a of seal lip 22 becomes more difficult to move along the inside surface of the side wall 26, thereby further increasing the sliding resistance between the glass run 10 and the door glass 32.
One option to prevent this increase in the sliding resistance, is to decrease the thickness of the side wall 26, thereby enlarging the distance between the projecting end 22a of the seal lip 22 and the inside surface of the side wall 26. With this arrangement, however, the thin side wall 26 tends to be undesirably deformed as the seal lip 22 is gradually pushed by the door glass 32 toward the side wall 26.
Another option is to decrease the thickness of the projecting end 22a of the seal lip 22, thereby reducing the force of the seal lip 22 against the inside surface of the side wall 26 resulting from the same displacement. With this arrangement, however, the durability of the seal lip 22 is reduced and undesirable undulations may occur along the thin projecting end of the seal lip 22 with the passing of time.
It is an object of the present invention to provide a glass run capable of preventing an increase in a sliding resistance of a glass run against a door glass even when the door glass is offset toward one of side walls of the glass run causing a projecting end of one of seal lips to press against an inside surface of the side wall.
The glass run of the present invention has a main body with a generally U-shaped cross section, which is configured to be attached into a channel provided along an inner periphery of a door frame, and a pair of seal lips which extend obliquely inwardly from open ends of side walls of the main body for holding a periphery of a door glass from both sides. An inclined surface is formed in one part of inside surfaces of the side walls of the main body, which ranges from the position corresponding to an projecting end of a facing seal lip to a bottom end of the side wall. The inclined surface is defined such that the distance between the inclined surface and a facing surface of the door glass which is held by the pair of seal lips gradually increases toward the bottom end of the side wall. When the door glass presses the projecting end of the seal lip on the inside surface of the side wall, the projecting end can move smoothly along the inclined surface toward the bottom wall, thereby minimizing any increase in the sliding resistance of between the door glass and the glass run.
The present invention can be preferably applied to a glass run of which the side walls are tapered to gradually decrease the distance therebetween toward the bottom wall of the main body.
In addition, the present invention can be preferably applied to a glass run of which one seal lip is longer than the other seal lip.
Other objects, features, and characteristics of the present invention will become apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification.